The Top 5 Garlic Pests (and How to Stop Them Organically)

Lessons From a Rough Garlic Harvest

A few summers back, I walked out to my garlic bed expecting to see sturdy green leaves standing tall. Instead, half the plants looked tired—silver streaks on the leaves, bulbs soft at the base, and a faint, unshakable sense that I’d been caught sleeping on the job. The pests hadn’t marched in with banners waving; they’d snuck in quietly, working under the surface and inside the stalks until the damage was done. That season taught me the hard truth: garlic pests don’t announce themselves, and if you don’t know what to look for early, you’ll lose more than just yield—you’ll lose time you can’t get back.

Today, I’ll walk you through the five most common garlic pests I’ve battled and how to beat them—without reaching for synthetic chemicals.

1. Onion Thrips – Tiny Bugs, Big Trouble

How to Identify Onion Thrips

Onion thrips are small, slender, tan-to-yellow insects—barely the size of a pencil tip. They hide between garlic leaves, especially in hot, dry weather. In USDA Zones 4–9, they tend to spike in mid-summer but can appear earlier in southern zones.

Signs of Damage on Garlic

Thrips scrape leaf surfaces and suck out plant juices, leaving silver or white streaks. Over time, leaves curl, turn brown, and bulb size shrinks.

Organic Control Options

• Neem oil or insecticidal soap sprayed weekly at first sign.

• Row covers to block adult thrips.

• Companion planting with basil or carrots to confuse pests.

Grandma’s Tip: “If your garlic leaves start to shimmer in the sun, don’t admire it—get to spraying.”

2. Bulb Mites – The Invisible Yield Thieves

How They Attack

Bulb mites move in through damaged cloves or wounds from harvest tools. Once inside, they feed on the basal plate and weaken the plant from the bottom up.

Prevention Through Rotation and Sanitation

• Follow a 4-year crop rotation—don’t plant garlic or other alliums (onions, leeks, shallots) in the same spot for at least four years.

• Clean tools with a diluted bleach solution between uses.

• Treat seed garlic with a short hot water soak (115°F for 20 minutes) before planting.

Pro Tip: Never plant garlic in the same soil that held onions, leeks, or shallots the year before.

3. Leafminers – Lines on Leaves You Don’t Want

Spotting the Damage

Leafminers are small fly larvae that tunnel between leaf layers, leaving winding white trails. In Zones 3–8, they often appear in early spring and again in mid-summer.

Organic Control

• Plant trap crops like spinach or chard to lure adults away from garlic.

• Use floating row covers during early growth stages.

• Remove and destroy infested leaves immediately—don’t compost them.

4. Rodents – Garlic’s Four-Legged Foes

Common Culprits

Voles, mice, and ground squirrels will dig up cloves, especially in fall and winter when food is scarce.

Physical Barriers and Deterrents

• Line garden beds with ½-inch hardware cloth buried at least 6 inches deep.

• Install raised beds with lined bottoms.

• Use deterrents like castor oil granules or predator urine.

Grandma’s Tip: “If you’ve got one vole, you’ve got a family. Treat it like you do mice in the pantry—fast and thorough.”

5. Nematodes – The Hidden Soil Enemy

What They Are

Nematodes are microscopic roundworms that attack garlic roots and bulbs. Once established, they’re hard to eliminate completely.

Signs of Infestation

Stunted plants, yellowing leaves, and deformed bulbs that store poorly.

Organic Management

• Solarize soil in summer by covering with clear plastic for 4–6 weeks.

• Plant nematode-resistant garlic varieties when available.

• Improve soil health with compost, cover crops, and diverse plantings.

Step-by-Step Guide – Protecting Your Garlic Organically

1. Inspect garlic plants weekly for pest signs.

2. Identify the pest before applying treatments.

3. Start with the least invasive organic method first.

4. Rotate crops every year and keep soil covered.

5. Keep a pest log—noting weather, dates, and treatments—to fine-tune your prevention next season.

USDA Zone Notes

• Zones 3–5: Pests tend to hit later but can be severe in short windows—row covers help.

• Zones 6–9: Longer warm seasons mean more pest cycles—weekly inspections are critical.

Faith Touch

Good stewardship means tending to the little things before they become big problems. Proverbs 27:23 says, “Be diligent to know the state of your flocks, and attend to your herds.” The same principle applies here: know the state of your garlic, and you’ll protect your harvest.

Lead Magnet / Printable Tool

Download the Garlic Pest ID & Treatment Quick Guide — a printable chart with photos, symptoms, and step-by-step organic control methods. Keep it in your shed or greenhouse for quick reference.

Closing – Keep Watch, Keep Growing

Garlic is tough, but it’s not invincible. The more you observe and act early, the fewer battles you’ll fight later. This week, take a slow walk through your garlic beds, look close, and trust your gut—if something looks off, check it out. Pests are sneaky, but a diligent grower is always one step ahead.